A Sixth Way?: Rational Souls and the Teleological Argument

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The following was a college essay written by Samuel Samson. It has been edited and approved by Ariel Hobbs. If you have a Theology essay that you would like published that received a grade of an A- or higher, please be sure to contact us.

By Samuel Samson, The University of Texas at Austin

St. Thomas Aquinas’s “Five Ways” are perhaps the most well known theological proofs for the existence of God. Yet while certain proofs—like the first way of a Prime Mover and the second way of a First Cause—tend to receive much attention, each proof is formidable in its own right. In this paper, I will discuss one such way; namely, the fifth way. I will begin by giving an overview of the arguments for the fifth way as posited by St. Thomas, including a discussion of its vital component: teleology. I will then discuss types of souls, as the telos of things relates closely to the character of their soul. From this point, I will discuss the objects of the fifth way, namely the behaviors of non-rational beings and how they align with the argument. However, I will also go further, addressing the question of whether rational beings also relate to the fifth way—whether the tele of man can also be used to prove the existence of God. With this question, I incline towards answering affirmatively. In conclusion, I will argue why the fifth way (or at the very least the teleological argument) can also apply to rational beings.

The Fifth Way

In the first part of the Summa Theologiae, St. Thomas Aquinas outlines what is known as the teleological argument for the existence of God: the fifth way.  In his words: “The fifth way is taken from the governance of the world. We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result. Hence it is plain that not fortuitously, but designedly, do they achieve their end. Now whatever lacks intelligence cannot move towards an end, unless it be directed by some being endowed with knowledge and intelligence; as the arrow is shot to its mark by the archer. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God” (ST I, 2, III). In particular, St. Thomas is discussing the fact that unintelligent things—be they inanimate objects, plants, or animals—act towards some nature or purpose. He cites observation of consistent behaviors or traits to be proof of this end, that this suggests that these ends are not random chance, but part of the thing’s design or nature. In these lines of the fifth way, we encounter its core concept: teleology.

Teleology argues that all things act towards a telos, or end. This is true for any tangible thing—dogs attain their end by barking and chewing on bones, flowers attain their end by growing vertically and blooming, rocks attain their end by remaining hard, stationary, and composed of sediment. We must note here that, in a sense, the telos of things is to be the most fully “realized” form of that thing—for the thing to accord to what it can best be by nature and design. A dog behaves as it does in an attempt to realize the natural ideal of “doginess,” the flower grows to achieve the end of “floweriness,” while even the rock, stationary as it is, attains towards the ideal of “rockiness.” It is from this striving for the ideal that we see the telos of a thing (regardless of whether it is achieved or not) is necessarily good for that thing. This is what St. Thomas means when he says that things act towards their telos “as to obtain the best result.” This argument echoes the classical tradition, namely Aristotle’s notion of the telos being the specific good of specific things, as opposed to some generic abstract notion of goodness. Thus, through observation, we can see that things tend towards an end, or telos, striving towards full realization of their design and nature, and that this pursuit is good. 

So how does teleology prove the existence of God? Here we encounter the necessity of an intelligent designer. St. Thomas asserts that nothing lacking intelligence can move towards its end without being directed by something with intelligence. He uses the example of an archer guiding the shot of the arrow. In other words, a golf ball is unable to fall into the hole by itself— it is only with the stroke of the golfer’s putter that it can do so. Thus says St. Thomas, all natural things must be directed towards their end by some intelligent being—that being God. It is important to note here that St. Thomas is not theorizing an anthropomorphic designer—a supernatural archer or golfer in the clouds. This notion would present contradictions and problems with the Divine attributes that are discussed elsewhere in the Summa. Thus, the fifth way is metaphysically reliant on the previous ways, understanding God the “designer” as one and the same—in will and intellect—with God the first mover and first cause. For this paper, it suffices to say that He is the first cause of all created things’ tele and the first mover who guides these same things towards these ends. With these other proofs as foundation, the fifth way too affirms the existence of God—the intelligent designer directing things towards their tele.

Types of Souls

Another important part of the fifth way is St. Thomas’s important distinction about unintelligent souls. In particular, he makes the distinction that unintelligent things cannot act towards their ends without something intelligent (God) to direct them. St. Thomas is describing the majority of created things—the heavens, the Earth, the plants, and the animals. Yet man is also a created being who is also intelligent, capable of directing things towards their ends. Archers and golfers are usually human, after all. Thus, how can we distinguish among the created things, particularly those living? For this, we have to discuss the anima—the soul—that which animates beings. As man and other creatures have different faculties, and therefore different types of soul, in order to better understand the fifth way, we ought to briefly discuss these versions.

The first, most simple type of soul is the vegetative soul. This is the type belonging to plants or other flora. The vegetative soul possesses the power to grow and reproduce, but it does not have the capacity to receive and react to sense impressions. For the telos of beings with vegetative souls aligns with these powers: to grow and to reproduce. A flower attains its end by sprouting and by reproducing through pollination. These are the highest acts that a flower could do, the peak of “floweriness.” Yet the vegetative being does not perceive that it does these things, it does it sense them. For this, we have to move to the next type.

The next type of soul is the sensitive soul. This type is more overtly synonymous to the descriptor of anima. True to the name, the sensitive soul possesses not only the vegetative powers of growth and reproduction, but also the ability to sense things and react to the environment. This manifests in different cognitive powers, including sensitivity to stimuli, instinct, and memory. We can observe these qualities in a dog, squirrel, or any other animal. So too are beings with the sensitive soul in possession of appetites and their consequent powers, the passions (or emotions). Sensitive beings can indeed feel—responding to stimuli in an emotional way. In this sense, a sensitive being, like a dog, attains to their telos by acting like a dog—reacting to stimuli (like growling at the notorious postman), eating, and learning to do tricks. Yet they are still limited in that they do not know why (or even that) they do these things. Indeed, there is only one earthly being which possesses this faculty.

The highest of the souls (at least in the earthly realm) is the rational soul, belonging to human beings. This is the soul that, beyond powers of growth, reproduction, sensation, and passion, is also in possession of reason—namely, an intellect and a will. These powers allow man to know what is good and act towards it. Therefore, as in the cases of vegetative and sensitive beings, rational beings attain their telos through exercising their knowledge and will. There are many acts by which man can exercise these faculties, but perhaps the highest of them are contemplation and love. There is nothing more fundamental to the intellect than contemplating truth and nothing more appropriate to the will than to loving what is good. St. Thomas argues that these two qualities—truth (ST I, 16, V)  and goodness (ST I, 6, I)—are perfectly manifested in God alone. Here the rational being’s telos becomes clearer.  There necessarily exists an object to which contemplation and loving are ordered. We cannot exercise our rational faculties without such. Thus the telos of the rational being is one of knowing the true and willing the good—and as God is the perfection of these things, it is ultimately the telos of the rational being to direct  his intellect and will towards God. As St. Thomas says himself: “rational creatures attain to their last end by knowing and loving God” (ST I-II, 1, VIII). This is the end towards which rational souls—human beings—incline.

The Telos of Unintelligent Beings

With this understanding of teleology and the types of souls, we can begin to see how the argumentation of St. Thomas’s  fifth way shapes up. Here we must address one slight point from the fifth way, namely that it only references teleology in regards to unintelligent beings and inanimate things—objects, plants, and animals. Thus, as explicitly stated by St. Thomas, the fifth way applies solely to unintelligent (or un-rational) souls—the vegetative and sensitive types. Indeed, he even further implies that this distinction is necessary precisely because intelligence is required on the part of God—the director—for the proof to make any sense. It makes sense how these types of un-rational souls would require an intelligent director—they do not possess intellects and wills by which they can know and act towards their ends by their own volition. In this sense, even humans, intelligent rational beings ourselves, can serve as directors. St. Thomas’s example of the archer shooting the arrow demonstrates this plainly. Thus, the distinction between unintelligence and intelligence is an important one, delineating between the directed and the director. 

The Human Question

This distinction raises another question—what I will call “the  human question:” Can the teleological argument apply to man, too? Indeed, it seems that St. Thomas is omitting human beings from the fifth way intentionally, and the argument holds if we apply it only to unintelligent things. However, we know that, like all earthly things, man himself has a telos, an end towards which he inclines. Yet man also is a rational being, possessing intelligence and capable himself of acting as a director-of sorts. Thus, I will spend the rest of this paper theorizing as to whether the fifth way (or perhaps a ‘modified’ fifth way) can indeed apply to man, too.

In the spirit of St. Thomas’s Summa Theologiae, perhaps we should start with a brief overview of some objections. The first objection says intelligent beings are directors, not the directed, and thus cannot be directed—God Himself, an intelligent being could not possibly have a director or else He would not be God. Therefore, the teleological argument cannot apply to intellectual beings because it would disprove God’s existence. 

The second objection suggests that since reason is the highest of faculties, and it is a faculty possessed by men, there is no need for a God as such a God would be like to men—hardly a God at all. As the archer shows, man is himself perfectly capable of being a director, so there is no need for him to be directed, too. 

Lastly, the third objection says that intelligent beings can act in ways contrary to their telos—for example, homosexual intercourse or suicide. Therefore, the intelligent being is able to direct himself, away from any sort of “natural directive,” as indicated by his ability to choose against his natural end. Therefore, there cannot be an omnipotent director over man.

I will begin by addressing these objections one by one. To the first objection, we must begin by stating that God does not need to be directed towards His end because He is His end in Himself—perfect actuality, constantly Being. As St. Thomas says: “It is therefore impossible that in God there should be any potentiality” (ST I, 3, I). He cannot be something with the potential to grow into his telos, as is the case with created things. That would place a limitation on God as both omnipotent and as creator, defeating the proof. In this way, God indeed cannot have a director, as there is nothing He can potentially be directed towards. On the contrary, we can observe that man, also an intelligent being, possesses a telos and yet also possesses potential to attain that end. Therefore, at the very least, there must be a logical possibility that man could be directed, regardless of whether he is or not. He can be both a director and be directed.

The second objection suggests that man and God possess the same high faculty of reason. Yet this is an incomplete picture. We know that man’s intellect is limited, finite just like every other aspect of his being. His body is necessarily temporal, prone to decay in death. His mind is likewise limited (finite) too. It is unreasonable to think that men can achieve perfect knowledge, that they can know about and how to do everything possible. Every man is limited in his knowledge in some way. This is obvious with children, but also with fully developed minds, too—a steelworker will likely not know the proofs and texts of the philosopher, as the philosopher will not know how to operate the tools and machinery of the steelworker. Thus, man is a finite intellect, while the same cannot be said of God. It is thus not proper to equivocate the two.

The final objection suggests that since man, in his intelligence, can choose against his telos, he does not possess a director and that therefore does not require God. Yet this objection forgets that even in choosing against the good, man still chooses these things in pursuit (or desire) of it. This is to say, as St. Thomas states: “because whatever man desires, he desires it under the aspect of good” (ST I-II, 1, VI). The homosexual engages in sodomy in pursuit of the goods of companionship, pleasure, and sexual fulfillment (even if these things cannot be found in such an act), just as the suicidal man, in his tragic act, seeks the goods of peace and aleviation of pain. As man’s telos is his ultimate end, good, and fulfillment, every decision he makes—even ones perverted or erroneous—is still intended towards it. Thus, we cannot say that man, as director, can reject his ends and forge his own path—he cannot help but act towards his ultimate end.

Written on the Heart

So can man, an intellectual being, himself require a director? I believe the answer to be yes. We can see this for many reasons. First, we must note that man is indeed distinct from plants and animals—vegetative and sensitive souls. His passions are properly subordinate to his rational powers, and thus he is indeed able to serve as a director in his own capacity. Yet as the response to objection two states, man’s intellect is finite, unable to fully understand all things. Further, as the response to objection three suggests, even in his free decisions, man still tends towards the good—even if in perverted or distorted ways. From these two realities of human nature, we can begin to see why man still needs God.

Man is an intellectual being with a rational soul. This has been repeated abundantly. Yet he is also a created being who possesses a telos—namely the end of knowing the true and willing the good. However, in order to know and will these things, he must also therefore know what is true and good that he might pursue them. How can man know right from wrong, good from evil? How can he know what his heart desires? What does it even mean for a thing to be good or true? Our finite minds can be a big hindrance here. It is difficult to deduce these things with absolute certainty or perfection—man is a mistake-prone creature. 

Yet we do know what is good and what is true, as we incline towards these things in every act we make. This is because the good and the true are indeed known by all, through what St. Thomas calls the natural law. This concept echoes what St. Paul says in scripture, who speaks of “the law written in their hearts” (Romans 2:15, Douay-Rheims). Namely, St. Thomas says that “the natural law belongs to those things to which a man is inclined naturally” (ST I-II, 94, IV), and that “acts of virtue and the virtues themselves are called natural” (ST, Supp., 41, I). Therefore, as with all created things, man always inclines towards the natural law, towards the good—even if he does not explicitly know he is doing so. This subconscious—or rather inherent—inclination towards the good derives from beyond man’s rational faculties. Indeed he can use his intellect to perceive the natural law, and his will to act in accordance with it—but besides these points he still cannot help but attempt to do so anyway (even if he does so in a distorted way). 

Therefore, there must be something which fills in the gaps of man’s finite intellect to the point that, like all created things, he always inclines towards his good. In other words, there still must be a director. St. Thomas corroborates this point, stating “the natural law is nothing else than the rational creature’s participation of the eternal law” (ST I-II, 91, II)—the eternal law being synonymous with God Himself. Thus, through man’s necessary inclination towards the good and his participation in the natural law, we see that man still is in need of some director—that command written on his heart. This being we call God.

Per a simple observation of human nature and behavior, we can see that man indeed inclines towards things good and true. This makes sense. Created things, intelligent and unintelligent alike, tend towards their tele. For men, this means knowledge and love, sharing in the true and the good. Here we must bring up one more question: where do we get truth and goodness from? Indeed, we see that there are gradients of truth and goodness—some things are partial truths or partial goods. Yet (as St. Thomas’s fourth way argues) if we are to say that there are imperfect versions of these things, there must exist some perfect form of them to which all others are compared, the “perfect gold standard.” However, we know that nothing on earth is perfect, at the very least in that it is temporal—guaranteed to expire eventually. We know this to be true, and thus we yearn for something beyond the temporal, something more perfect than the imperfect world in which we live. So what is this perfect, eternal truth and goodness? This question was already answered earlier in the paper—God himself. Ultimately, all things good and true are reflections of God who is goodness and truth—absolute perfection—Himself.

Yet man, at least on Earth, cannot observe God directly. He cannot actually fully know or see the perfect form of that which he seeks—but he still seeks anyway, occasionally in the wrong direction, but seeking nonetheless. This we might call faith—described in scripture as “the substance of things to be hoped for, the evidence of things that appear not” (Hebrews 11:1, Douay-Rheims). In faith, we believe in that which we cannot tangibly observe, rest in that which we do not fully comprehend. In this way, man also needs God to fill in the gaps of our finite intellects—infusing us with faith that we might be guided towards our telos. Faith is, as St. Thomas describes a theological virtue, meaning that it is “infused in us by God alone” (ST I-II, 62, I). This infusion of Divine grace we might call “direction” in itself, an elevation of our gaze towards the supernatural in a way we could never do alone. Faith is an explicit call by God towards our ultimate end of knowing and loving Him. Our finite intellects cannot fully comprehend God, and therefore cannot fully comprehend neither the good nor the true. Yet faith, an infused gift from God, allows us to aspire towards that which we cannot see. Therefore, even though rational, the theological virtue of faith (along with the other undiscussed virtues of hope and charity) demonstrates that man still needs God’s direction as he pursues his end.

Man is unique within creation in that he possesses a rational soul, an intellect and will by which he can know and love. Yet he is still finite, and therefore still requires a director to guide him towards his ends. In this capacity, God is not a nanny-figure who channels man without deviation towards the good and true—man must still choose these things for himself. But the desire for these things forever remains written on his heart, the inclination towards them always present in his actions. In this sense, the fifth way, albeit with a bit more contextualizing, still applies to human beings, too. Perhaps the argument is different enough to call it a “sixth way” in its own right. Regardless, we know that man inclines towards his telos—God Himself. We seek truth and goodness that we know, but do not fully understand, that we perceive, but do not fully see—with the faith that one day, guided by His grace, we might experience Him in fullness forever. 

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